In order to achieve a high speed printing disc, it is necessary to make the arms of the disc very flexible and light in weight so as to accommodate rapid printing impacts. Many flexible and light weighted plastics are available for this purpose. However, if a high quality of printing is also a requirement, then it is necessary to have the character face of each arm of the disc composed of a material that is hard and durable.
Because the material requirements for high speed printing and quality printing are diametrically opposite, a compromise was originally sought for the disc material.
Many tests, however proved that no adequate compromise could be made. Neither was it found possible to plate over the character surface of the arms without substantially destroying the crispness of the character image.
Furthermore, the method of electroforming a metallic cover upon the flexible plastic character head was not entirely satisfactory, because serious cracking developed in the metal after a relatively small number of impacts.
A pure metal print head attached to the plastic arm was not satisfactory. The metal print head had the necessary structural strength, but weighed too much for high speed printing.
The present inventive composite printing disc assembly seeks to achieve the objective of providing a disc that can operate at high speeds and deliver a high quality of printing.